I also elevate on a pillow to keep some of it in. Although, I did read somewhere not to elevate your hips too high (stand on head, etc!) because the semen/sperm will actually form like a pool around your cervix, not giving sperm the opportunity to swim in.

I was told to elevate hips for 20-30 mintues after sex to allow sperm to get in the right direction. I still leak afterwards too and get aggravated thinking none is getting where it should go. Thanks for asking! I was wondering too.

One way to prevent some of it from leaking out is to orgasm AFTER he has ejaculated in you. When a woman has an orgasm her cervix, the mouth of the uterus, contracts as the uterus moves. This causes the uterus to dip or bob into the vagina. If the male has already had an orgasm, then this area is rich in semen (sperm). This motion of the cervix will actually draw the semen into the cervix and uterus to aid in it's passage towards the ripe egg.
An orgasm prior to male ejaculation can help make the sex more pleasurable, the vagina more lubricated and make the whole scene much less clinical. However, for reasons stated above, if you do not have an orgasm after the male's then it is imperative for you to acheive one. It does not matter if this orgasm is via masturbation (self or partner lead). It simply needs to occur to improve the chances of pregnancy.